sensing body position -
- lateral line system - helps fish sense objects from vibrations around them
- mov’t in environment causes stereocilia (hair) on cupula membrane to move >> action potential >> messages sent to brain
- bending of hair can have excitatory/inhibitive effects, depending on direction of bend
- statocyst - allows invertebrates to move themselves in respect to gravity
- cilia embedded in calcium carbonate
- cilia bends when position changes
- vestibular apparatus - saccule, utricle, semicircular canals used to determine position in vertebrates
- similar to mechanism used in lateral line system
- hair found in otolith membrane
- utricle more sensitive to horizontal mov’t, saccule more sensitive to vertical mov’t
- semicircular canals - gives sense of angular acceleration
ear - actually works better in water than air
- outer ear - air vibrations travel through ear canal to eardrum (tympanic membrane)
- middle ear - contains 3 ossicles (small bones): malleus (hammer), incus (anvil), stapes (stirrup)
- connected to throat by Eustachian tube to equalize air pressure
- inner ear - contains cochlea (contains cochlear duct)
- vestibular/tympanic canal located on top/bottom of cochlear duct
- all 3 chambers filled w/ fluid (vibrations >> fluid pressure waves)
- organ of Corti - contains basilar membrane, hair cells, tectorial membrane
- stimulation of hair cells >> action potential >> impulses interpreted as sound
- different fiber lengths in basilar membrane >> different pitch
- sonar - direction of sound easily determined due to location of 2 ears
- distance of sound hard to determine due to environment
- echolocation - emitting sounds and using the time it takes for the sound to come back in order to determine location
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